Lysosomal storage diseases are a group of over 40 disorders which are the result of defects in genes encoding enzymes that break down glycolipid or polysaccharide waste products within the lysosomes of cells. The enzymatic products, e.g., sugars and lipids, are then recycled into new products. Each of these disorders results from an inherited autosomal or X-linked recessive trait which affects the levels of enzymes in the lysosome. Generally, there is no biological or functional activity of the affected enzymes in the cells and tissues of affected individuals. Table I provides a list of representative storage diseases and the enzymatic defect associated with the diseases. In such diseases the deficiency in enzyme function creates a progressive systemic deposition of lipid or carbohydrate substrate in lysosomes in cells in the body, eventually causing loss of organ function and death. The genetic etiology, clinical manifestations, molecular biology and possibility of the lysosomal storage diseases are detailed in Scriver et al., eds., The Metabolic and Molecular Basis of Inherited Disease, 7.sup.th Ed., Vol. II, McGraw Hill, (1995).
TABLE I ______________________________________ Lysosomal storage diseases and associated enzymatic defects Disease Enzymatic Defect ______________________________________ Pompe disease acid .alpha.-glucosidase (acid maltase) MPSI* (Hurler disease) .alpha.-L-iduronidase MPSII (Hunter disease) iduronate sulfatase MPSIII (Sanfilippo) heparan N-sulfatase MPS IV (Morquio A) galactose-6-sulfatase MPS IV (Morquio B) acid .beta.-ga1actosidase MPS VII (Sly disease) .beta.-glucoronidase I-cell disease N-acetylglucosamine-1- phosphotransferase Schindler disease .alpha.-N-acetylgalactosaminidase (.alpha.- galactosidase B) Wolman disease acid lipase Cholestrol ester storage disease acid lipase Farber disease lysosomal acid ceramidase Niemann-Pick disease acid sphingomyelinase Gaucher disease .beta.-glucosidase (glucocerebrosidase) Krabbe disease galactosylceramidase Fabry disease .alpha.-galactosidase A GM1 gangliosidosis acid .beta.-galactosidase Galactosialidosis .beta.-galactosidase and neuraminidase Tay-Sach's disease hexosaminidase A Sandhoff disease hexosaminidase A and B ______________________________________ *MPS = mucopolysaccaridosis
As a representative of the class of lysosomal storage diseases, Fabry Disease is a recessive, X-linked inherited recessive disorder caused by a deficiency in the lysosomal enzyme .alpha.-galactosidase A. Absence of this lysosomal hydrolase results in progressive deposition of the glycosphingolipid globotriasylceramide (GL3), or galactosyl-(.alpha.1-&gt;4)-galactosyl-(.beta.1-&gt;4)-glucosyl-(.beta.1-&gt;1')-ce ramide, in most tissues of the body. The birefringent deposits of GL3 are primarily found in the vascular endothelium. Progressive endothelial accumulation of GL3, leads to ischemia and infarction in organs such as kidney, heart or brain, causing excruciating pain, kidney failure, cardiac and cerebrovascular disease. The average age of death for an affected individual, from renal, cardiac and/or cerebral complications of the vascular disease, is 41 years. There are no effective treatments currently available for this disease. (See, e.g., Desnick et al., in Scriver et al., eds. The Molecular Basis of Inherited Disease, 7.sup.th Ed., Chapter 89, pp.2741-2784, McGraw Hill (1995)).
Human .alpha.-galactosidase A (.alpha.-D-galactoside galactohydrolase; .alpha.-gal A; EC 3.2.1.22) is a lysosomal exoglycosidase encoded by a gene on Xq22. A human liver cDNA that codes for .alpha.-galactosidase A was isolated from a .lambda.gt11 expression library (Calhoun et al., Proc. Natl. Acad. Sci., USA 82:7364-7368 (1985)). The isolated cDNA encoded the mature amino acid sequence of .alpha.-galactosidase A but did not contain the complete signal peptide sequence of the precursor form (Bishop et al., Proc. Natl. Acad. Sci., USA 83:4859-4863 (1986). This partial cDNA clone was then used to construct an E. coli expression vector with the .alpha.-galactosidase A coding sequence under control of the trp promoter (Hantzopoulos et al., Gene 57:159-169 (1987)). A genomic clone was later isolated which carried the promoter and first exon of the protein including the full signal peptide (Quinn et al., Gene 58:177-188 (1987)). Further, full length cDNA clones isolated from human fibroblasts were obtained and used to obtain transient expression of .alpha.-galactosidase A in COS cells (Tsuji et al., Eur. J. Biochem. 165:275-280 (1987)). Recently, a Fabry knockout transgenic mouse demonstrating a deficiency in this enzyme activity has been made (Ohshima et al., Proc. Natl. Acad. Sci., USA 94:2540-2544 (1997) knockout mice display a complete lack of .alpha.-galactosidase A activity). Lipid analysis of the liver and kidneys of the knockout mice revealed a marked accumulation of GL3 over time, indicating the similarity of the pathophysiological process in the mutant mice and in patients with Fabry disease. Id. Thus, the Fabry knockout mice provide an excellent model for the human disease.
De Duve first suggested that replacement of the missing lysosomal enzyme with exogenous biologically active enzyme might be a viable approach to treatment of lysosomal storage diseases. De Duve, Fed Proc. 23:1045 (1964). Since that time, various studies have suggested that enzyme replacement therapy may be beneficial for treating various lysosomal storage diseases. The best success has been shown with individuals with type I Gaucher disease, who have been treated with exogenous enzyme (.beta.-glucocerebrosidase), prepared from placenta (Ceredase.RTM.) or, more recently, recombinantly (Cerezyme.RTM.). It has been suggested that enzyme replacement may also be beneficial for treating Fabry's disease, as well as other lysosomal storage diseases. See, for example, Dawson et al., Ped. Res. 7(8):684-690 (1973) (in vitro) and Mapes et al., Science 169:987 (1970) (in vivo). Clinical trials of enzyme replacement therapy have been reported for Fabry patients using infusions of normal plasma (Mapes et al., Science 169:987-989 (1970)); .alpha.-galactosidase A purified from placenta (Brady et al., N. Eng.J.Med. 279:1163 (1973)); or .alpha.-galactosidase A purified from spleen or plasma (Desnick et al., Proc. Natl. Acad. Sci., USA 76:5326-5330 (1979)) demonstrated the biochemical effectiveness of direct enzyme replacement for Fabry disease. These studies indicated the potential for eliminating, or significantly reducing, the pathological glycolipid storage by repeated enzyme replacement. For example, in one study (Desnick et al., supra), intravenous injection of purified enzyme resulted in a transient reduction in the plasma levels of the stored lipid substrate, globotriasylceramide.
However, to date, the biochemical and clinical effectiveness of enzyme replacement in Fabry disease, as well as other lysosomal storage diseases, has not been demonstrated due to the lack of sufficient human enzyme for adequate doses and long-term evaluation.
Accordingly, there exists a need in the art for methods for providing sufficient quantities of biologically active lysosomal enzymes, such as human .alpha.-galactosidase A, to deficient cells. Additionally, there exists a need for new vector compositions that allow for efficient transfer of genes encoding lysosomal enzymes, such as .alpha.-galactosidase A, to deficient cells and at the same time direct expression of the transferred gene. Recently, recombinant approaches have attempted to address these needs, see, e.g., U.S. Pat. No. 5,658,567 issued Aug. 19, 1997 for Recombinant alpha-galactosidase A therapy for Fabry disease; U.S. Pat. No. 5,580,757 issued Dec. 3, 1996 for Cloning and Expression of Biologically Active alpha-galactosidase A as a Fusion Protein; Bishop, D. F. et al., Proc. Natl. Acad Sci., USA. 83:4859-4863, (1986); Medin, J. A. et al., Proc. Natl. Acad. Sci., USA. 93:7917-7922, (1996); Novo, F. J., Gene Therapy. 4:488-492, (1997); Ohshima, T. et al., Proc. Natl. Acad. Sci., USA. 94:2540-2544, (1997); and Sugimoto Y. et al., Human Gene Therapy. 6:905-915, (1995). In addition, in allowed U.S. patent application Ser. No. 08/466,597, filed Jun. 6, 1995, incorporated herein by reference, retroviral expression vectors containing a gene encoding human .beta.-glucocerebrosidase were shown to infect autologous hematopoietic stem cells, which when retransplanted into a Gaucher patient provided sustained production of biologically active enzyme to the patient.
To date, however, there has not been a vector composition that has proven capable of transducing and sustaining expression of the human .beta.-galactosidase A gene, or most other genes encoding lysosomal enzymes to cells that are deficient therein. The present invention satisfies these needs and provides related advantages as well.